Gear or gearing



J. pggwg GEAR on GEARING Filed Oct. 24. 1929 2 Sheets-Sheet 1 3;)32. J.PQTTS GEAR OR GEARING Filed oct. 24, 1929 2 Sheets-Sheet 2 T OF F l EEEO'I'TSJIOFJLONDON, ENGIJAND 110 that ithey 'zrotate itogether with 4adesired amount of a angiilar ;play between =:-them. hesef intermediateagear wheelsare; mounted :axiallyiin Ffront ofionerxofithe igear wheelsto be engaged (hereinafter calledtheifirstrmaLin P :gear 'zwheel) :andare :so disposed .that the iteethtdfltheiother wheel tolbetiengaged(hereinafter termed :the .second. main ge'ar fwhel) ztermedi ate wheelsbeforegp'assing to the teeth 520 o'fctheifirstmaingear zwheel.

lMeans;are providedforffrictionallyengage'onemf ithe Finter'mediate.;..gea'r wheels i (hereinafterztermeditheffrictional intermedi- ::ate1;ge'ar whel) whenz require d withathefirst n1ainggear "wheeL- so athat:it 1 is caused :toturn atherewith,whilsttheiother intermediates gearxwhel :ithereinafterrtermeditheifreeiintermediate;- ear wheel) imayibeFincconstantamesh with the-second maimgear wheeluor comeiin :a[desired r position adj aceiiti the:.said second iim'ain gear wheel. a

The imeans for :causing the frictional ten- .gagementbetweentheifrictional'. intermediate .1 gear" wheel andtthez firstzmain gearwheel'may 1be constantlyeeifective or:mayizbeibroughtinto action or:enhanced 'i by the movement :to En- ;,.gage the mainigear "-wheels,tandConsequently 'when it is a desired =tocenga'ge the main ear whe'1s, the:first movement causes "the r ric- 40 itional interme diatewheel to turnwith and at thesame-speed as'tthefirst maingear wheel. At the :samesamertime the secondmain .gear wheellhasengagedor is in engagement with-the :free intermediate zgear wheel. .I'If the consequent speeds of the.intermediate gear wheels idifler, they "therefore will rotate a smallangular "extenttat .diflerentspeeds so :th'atithe :teeth of ithefrictional intermediate gear-wheel will form "a bar or impediment 550.to the iifurther engaging movement of :the

QGEARING 402,138,1'azidilnfireati-Brttain time 25,:1-929.

psecondamain gear wheel. The parts remain zin thisiconditionuntil'the'linear speeds of ithegpit'chzcircles 59f the main. gear.wheels .becomethe'csame,"theafrictional engagement of "thefrictionalintermediate gear wheel perzmittingtthe necessary slip,.and atthe-same 5 time the'teeth of the interlnediategear wheels .are .graduallybrought into coincidence per amittingithejpassageofxthe secondmain gear wheel'toitheteeth ofithe frictional interme- 60 diaten ge :11"wheel. This last mentioned wheel lhy its frictional engagement with thefirst 'main gear'wheel isiturned at the same speed :asathessaidufirstmain gear wheel, and consequently the1second main gear wheel is free rto'sli de-zeasily into engagement with the first .imain gaan wheel.

fManyxforms offlgears and gearing can be constructed according totheinvention, and ingmost casesij; isipreferred that the connec- :tionhetween 1 the I intermediate f gear wheels shall "be r a :pin and islotconnection, \the: slot orrr-slotsfhaving' a desired circumferentialexitent, ipreferahly permitting a -movement equal 'to thevcircumferential pitch between ctwo teeth, 1 although this .movement maybe ,iless i.or';more-.-as desired.

"Where reqiiireditheientering:andeexit faces 1 of the teeth of 1 thegears, intermediate 'or imain,rmay' be"rounded,"especially' in the casesof l the teeth :of the frictional intermediate -gear wheeltandsecondmain gear wheel.

Suitable :friction means such as a-ferrodo :disc'orithe'likemay"beyprovided between the Ifriction'alintermediate gearwheel and the flirstimain gear wheel and :the intermediatewhelsmay-normally be guite free from axial pressure, 50 that nofrictional engagement 'takes'place.

Axial pressure may :.be provided by a suitable-spring orsprings'to give.a frictional grip, "and this may be enhanced or replaced ".by::an=:axialthrust due to the movement of :thesecond gear'wheellby'reasonof the camlike .jaction iduetolthe'rounded ends of the 9 teeth.

The intermediate fgear wheels may be mounted loosely upon'ithe shaft ofoneof the main; gear wheels or upontheirown particu- Iilar;-shaft,.andfintsomeacases one of the intermediate gear wheels, for" example thefrictional intermediate gear wheel, may be formed with a sleeve, uponwhich the other intermediate gear wheel is mounted to turn.

In order that the invention may be better understood, it will now bedescribed with reference to the accompanying drawings in which Fig. 1shews a sectional elevation of one method of carrying the invention intoeffect.

Fig. 2 shows an end elevation of a portion of Fig. 1.

Fig. 3 shews a similar view to Fig. 1, of another method of carrying theinvention into efi'ect. v

Figs. 4 and 5 shew elevations of detached details.

Figs. 6 and 7 shew fragmentary views illustrating the action of certainparts.

Fig. 8 shews a sectional elevation and Fig. 9 an end view of anothermethod of carrying the invention into effect.

Fig. 10 shews asimilar view toFig. 8 with the parts in another position.

Fig. 11 shews asectional elevation through the gear box of a motor car,with the invention applied to certain of the gears thereof.

Fig. 12 shews a sectional side elevation of a portion of Fig. 11 toillustrate the reverse drive.

Fig. 13 shews a fragmentary sectional elevation on the line 1-3-13, Fig.12.

Fig. 1e: shews in elevation gear details associated with the form of theinvention sh'own in Figs. 11 to 13. a

The particular form of gear constructed according to the invention andshewn in Figs. 1 and 2 comprises a first main gear wheel mounted uponand keyed to a shaft 21. This gear wheel 20 is recessed at 22 on oneface and has located in the recess a ring 23 of ferrodo or othersuitable frictional ma terial, the outer surface of which projectsbeyond the surface 24 of the gear wheel 20. The shaft 21 extends beyondthis frictional ring 23 and has mounted thereon a frictionalintermediate gear wheel This has the same number of teeth and diameteras the main gear wheel and is formed with a sleeve 26. The free intermediate gear wheel 27 is mounted upon the sleeve 26 and this again has thesame diameter and number of teeth as both the frictional intermediatewheel and the first main wheel 20. The outer surface 28 of the freeintermediate wheel 27 comes flush with the end of the sleeve 26 and theshaft 21 is shoul dered at 29 to form a stop or abutment to hold theintermediate wheels 25 and 27 in position, whilst permitting them aslight amount of axial play to enable the frictional intermediate wheelto come out of engagement with the ring 23 of ferrodo or other material.The frictional intermediate gear wheel 25 is provided with one or moreslots 30 of desired circu1nferential extent and the free intermediategear wheel 27 has a corresponding number of pins 31 which enter the saidslots 30. The amount of circumferential move ment permitted between thetwo intermediate wheels 25 and 27 is substantially the pitch distancebetween the teeth of the gears. The teeth at the entry faces of thefrictional intermediate gear 25 and the first main gear 20 are roundedat 32 and 33 respectively.

The second main ear wheel 34 is mounted to turn with a sha t 35 parallelto the first shaft 21 and is adapted to move axially, either by axialmovement of the said shaft or by sliding upon a featherway or the like36'upon' the said shaft. This second main gear wheel 34 normally runs inmesh with the free intermediate gear wheel 27";(in the )osition shewndotted in Fig. 1) and the entry aces of its teeth are rounded at 37'.

In action, in order to engage the-main gear wheels 20 and3t, the secondmain gear wheel 34 is slid until the rounded ends 37 of its teeth pressagainst the rounded ends 32 of the teeth of the frictional intermediategear wheel 25. This action causes frictional grip between the frictionalintermediate gear 25 and thefirstmain gear 20. The frictionalintermediate gear 25 is .then subjected to two forces (1) the turningmovement-of the first main gear 20,.and (2) the turning movement due tothe axial thrust of the second main gear 34:. If the linear speeds ofthe pitch circles of the main gears 20 and 34: are exactly the same,then the two intermediate gears 25 and 27 are rotated at the same speed,

and the axial thrust of the second main gear 34 brings the gaps in theteeth of the intermediate gears into alignment by the interaction of therounded cam-like ends 37 and 32 so that further axial movement of thesecond main gear is permitted, to enable its teeth to mesh with those ofthe frictional intermediate gear 25. The rounded ends 37 of the secondmain gear 34 and 33 of the first main gear 20 now come adjacent and asthe gears are rotating with their pitch circles at the same linearspeeds, the curved ends permit easy engagement between the main gears.

If, however, the linear speeds of the pitch circles of the maingearsdiffer, then the two turning movements acting upon the frictionalintermediate gearj25 cause relative movement to take place between thetwo intermediate gears, which is permitted by the slots and pins 30 and31, the direction of the relative movement varying according to which ofthe main gears has the greater linear speed, and this brings the teethof each intermediate gear wheel opposite to the spaces between the teethof the other intermediate gear wheel and the pins 31 to one end or otherof the slots 30. Thus the second main gear wheel cannot come fully intomesh withthe in I become the same or substantially the same then thethrust of the teeth of the second main gearwheel 84' on" the frictionalintermediate wheel 25, acting as before in a camlike manner, causes thesaid frictional int?! mediate gear-wheel to 'heturnedrelatively to thefree -intermediate gear wheel 27 (re moving the pins 31 from the ends ofthe slots to an intermediate position) tobring the gaps in the teethbetweenthe intermediate gear Wheels into alignment. In this manner'asbefore explained axial movement of the second main gear 'Wh'ee can :be;continued'' until the main gears come into mesh; l v

. Asin't-heform ofith invention shewn i Figs. 1 and 2, even whenthGfSQCOIlCl main gear wheel is in -enga'g'ement'I with the firstmaingear'wheel thes'aid second main gear Wheel 3ststillaemains'in'm'esh-with the tree intermediate gar 27, it will 'be understood thatno diifi ulty-is experienced in'disengaging the genes from the gear I"Figs; 4 and" ashew-rajce' views ofthe in} termediate' igear Wheels suchfor feitample as an'd'Q'l, each having si-slerso and a pin 31 and sodisposed that'the 'pin'3lof one gear canenter the slot '0't the othergear.

Figs. 6 and '7 illustratehow the teeth of one intermediate gear projectover-the gaps between the teeth of the other gear when tie pin 31 isbrought to the end of the slot 3 In Fig. 6 it 'will'be seenthat when theparts are in this positio'n' the gaps in one gear wheel are fullycovered by the teeth of the other. gear wheel whilst in Fig. 7 in thecorresponding position the gaps are only partly obscured by the teeth.In either case the position is such that when the pins 31 are in anintermediate position in the slots 30 the gaps of both intermediate gearWheels are in coincidence,

According to another and somewhat similar form of the invention, shownin Fig. 3, the frictional. and free intermediate gears 38 and 39respectively are madethe same and they are bot-hloosely mounted upon theshaft 21 ofthe first main gearQO, arin; 40 of ferrodo or other suitablematerial being mounted around the shaft between the first main gear 20and the frictional intermediate gear 88 coming adjacent'thereto. Eachintermediate gear has a circumferential slot -11 of desired extent,and-in a diametrically opposite posit-ion projecting pin the arrangementbeing similar to that shewn in Figs. 4% and this means when theintermediate gearsare mounted upon the shaft the pin 42 of one comesintowthe slot 41 of Wheel. 3

the other. The entry and exit faces of the teeth of both intermediategears are rounded and a compression spring 43 is provided upon the shaft521, abutting atone end against a.

shoulder 4:4: thereon, and at theo'ther end against the freeintermediateWhee1'39, to keep these gears 39 and 38 the first main gear,20. g

The second main gear 3-1 inthis case has its teeth rounded is not inengagement with the free intermediate gear 39 (as shewn in full lines inFig. 3), but, when it is desired to engage'the main gears, the firstmovement hrlngs the second main gear 3% into engagement withthe teeth ofthe freefllntermediate gear 39 and then the action is similar tothat-previously described.

'Ineithercasc When'in engagement with the first main gear 20, the secondmain gear 34 =mayhe"free of the teeth of theintermediate'gears or maystill he in engagement therewith. hen, however, thearrangement issuchthat the second main ge'ar "84 i s i' free,

theexit faces'of the teeth of thegeais 3 1,

38 and 39 must he rounded to permitth'e ready. disengagementof the maingears."

' In some cases one of the main gear wheels may he an internal clutchmemhen?such: as

an internally toothed annulus hut it vfillfjhe pressed towards at eachend and normally realized thatthe action will. helthe sani1e as thatpreviously descrihed, es necially' if the intermediate clutchmemhers'are associated with the other main clutchflmeinher In suchconstructions thefree intermediate clutclrinemher be in mesh ivith theannuluswhen the main clutch members are out of engagement, 'orotherwise, as desired. In a preferred casewithsuch a constrr tion and asshewn in Figs. 8, 9 and 10, the

first and second'main clutch members 45 and 46 have the same number ofteeth and diameter. In this instance the shafts 21 and 35 come inalignment and when the main clutch members are in engagement the twoshaft-s drive solid, but as Will he understood the said clutch memberscan only be brought into engag merit through frictional and freeintermediate clutch members 47 and 48 respectively, and then only whenthe speeds of the respective shafts are the same.

In the arran ement shown in Figs. 8 9 and -10, the frictional and freeintermediate clutch members are shewn constructed and interconnected ina manner similar to those illustrated in Fig. 1, and a friction disc 49is disposed in a recess in one face of the first main clutch member 45,sothat it projects therefrom to engage with the adjacent face of thefrictional intermediate clutch member 47. The int rmediateclutelrmemhers are maintained in position on the shaftQl by means of anut device 50 which forms an abutment, permitting very slight axialplay.

' The disengaged position of the main clutch members is shown in Fig.and from this figure it will be seen that in the disengaged position thesecond main clutch member .46 remains in mesh with the free intermediateclutch member 48.. If desired, however, the

arrangement may be such that in the disengaged position of the mainclutch members, the second main clutch member 46 comes out of engagementwith the free intermediate clutch member 48. l-Yha-tever the arrangement, however, it should be noted that where required the ends of the"teeth of any of the clutch members may be rounded to facilitate theengagement of other gears.

Fig. 8 shews the main clutch members in engagement, and it will beappreciated from gare'that the whole et'ic'e, including and all-theclutch members, rotates SGI It should in all cases be understood thatthe teeth of the intermediate gear wheels are so relatively to theirinter-en agin and to -=each other, that when t e sai wheels in eitherdirection have reached their extreme relative positions, then the teethon te free intermediate gear wheel, bar or partially bar the .apsbetween adjacent teeth of the .friction'a' intermediate wheel. In thismanner when the intermediate gear wheels rotating fat difi erentspeedsfrom the first main gear wheel, then the teeth of the fricintermediate:gear wheel are displaced in relation to the teeth of the freeintermediate gear wheel, thus 'greventi-ng the second main gearwheel,whic .is driving the intermediate ggcar wheels, from sliding intos went with the first main gear wheel,

when theffirst main gear wheel is rotating at the a as the intermediategear or preferablya little faster. .The natmall drag th ns :cmses tlheintermediate heel to move in relation to 'i irtemediate gear wheel untilthe teeth are opposite to one another, when the second main gear wheelcan be moved into engagemerit the first main gear Wheel, by :passing throngh the teeth of the frictional intermediate gear wheel.

slot and pin, or other equivalent connecting me azns between theintermediate gear wheels maybe arranged so that displacement can takeplace in either direction, or in one direction only as desired.

Referring to Figs. 11 to 14'; in these fig a practical application ofthe invention is strewn, comprising various pairs of first and maingears, with associated frictien al and ilfree intermediate gears, asutifli'zed in the gearbox of a motor road vehicle.

In '11, 51 is the engine shaft which drives through gearingin the usualmanner in "counter shaft 52, which counter-shaft zhas keyed theretofirst main gear Wheels 53 and 65 Associated withthe first maingea-rwheel 53 a pair of intermediate gear wheels com-- prising africtional intermediate gear '55 and a free intermediate :gear 56 a ringof friction material 5? being disposed between the face of thefrictional intermediate gear (55 and the adjacent face of the firstrnain gear 53. The intermediate gear wheel-s and 56 and the frictionring 57 are mounted around the boss of a gear wheel 5 81-1011 thecountershaft 52 and are kept pressed towards the first main gear 53 by:a compression spring 59.

60 is the driven shaft hating splined thereon slidahle second mainfi'lyand 62,

which are adapted to lhe'mowed from the gear lever '63 in .a .kn own Thesecond main :gear 61 tor-ms the gear be associated with the main gear:53, and for this purpose the intermediate gearsrhfi, are located in aposition intermediate main gears "53 and '61, the action similar to thatexplained with reierence to Figs. '1 and 2 or 3.

Associated with gear .54.- is a pair of intermediate gears, -cornprising:a frictional intermediate gear '63 and a tree intermediate gear 64mounted freely on the shaft 52, with a ring of friction material 65between the intermediate gear 153 and the main gear 554. Thegears16-3Q64the ring 6'5 are keptpressed towards the main gear .54 hy a compressionspring :66 mounted around the shaizt I second main vgear 62 'sli-dableon the shaft 60 is adapted to co-operate with the having associatedtherewith a rirrgoif friction material '70, the whole 'iheing mountedfreely upon the boss of the gear .67 and kept pressed towards the saidwheel a compression spring 71, the :gear .62 acting :as the second maingear the reverse drive.

the drawings, the intermediate gears are connected together, in -orderto have the desired :small amount of relative angular movement, byforming eachgear with a recess or notch 7E2 opening into its centralbore, and with a pressed or turned round tongue '73 in a diametricallyopposite position, the arrangement being such that the "pressed ir ptongue of of intermediate gears enters into the -recess of otherassociated intermediate gear, the circumferential extent of the recessIheing a desired amount greater "than the circumferential extent of thetongue'73.

In the embodiment shown Figs. 11,12,

no first main gear 54 the intervention of 13 and 14, the invention isshewn applied to the bottom, second and reverse gears, but not to thetop gear which is of ordinary construction, but it will be realized thatthe top gear can be formed in a manner similar to that shewn anddescribed with respect to Figs. 8, 9 and 10, if desired, and by thismeans when in top gear the shaft 35 is driven at the same speed andsolid with the shaft 21.

In some cases spring or other means may be employed normally to keep theteeth of the intermediate gear wheels in line, until relativecircumferential movement causes the said teeth to be relativelydisplaced.

Where a spring is employed for creating initial friction between thefrictional intermediate gear wheel and the first main gear wheel, thearrangement of this spring can be varied as desired, as well as itspressure.

In the case of change speed gears for ma-' chine tools, or for otherpurposes, where the changing may take place under no load and where noclutch is employed, the friction created by the spring may cause theintermediate gears to synchronize in speed and enable the second maingear to travel into mesh.

Gears and gearing constructed according to the invention areparticularly suitable for application to the gear boxes of motorvehicles and one such constructional embodiment has been described, butmany other constructional forms can be utilized according to theparticular nature of the gear box. Further, in all cases any number ofgear protecting arrangements according to the invention may be used,depending upon the particular circumstances in any gear combination.

The two intermediate gearscan be arran ed either on the driving ordriven shat s, and may be arranged to slide with the gear moving intomesh or may be arranged in front of the fixed main gear to be engaged.

The invention is not limited to the precise forms or details ofconstruction de-' scribed, as these may be varied to suit particularcases.

What I claim and desire to secure by Let-' ters Patent of the UnitedStates of Amer- 10a is 1. Automatic means for protecting the teeth oftwo main toothed gear wheels (termed the first and second main gears)which are to be brought into engagement by relative axial movement,comprisingtwo coaxial intermediate toothed ear wheels (termed thefriction and free intermediate gears) each having the same diameter andnumber of teeth, which teeth are siiitable to be engaged by the teeth ofthe second main gear, interconnecting means between the friction andfree intermediate gears including a lost motiomdevice, so that the saidinthe friction intermediate gear driven by the first main gear, thearrangementbeing such that, when the main gears are relatively movedtowards their engaging position, if the linear speeds of the pitchcircles of the main gears are the same no relative rotary.

movement takes place between the intermediate gears, and the second maingear is free to be relatively moved successively into engagement withthe friction intermediate gear and then into engagement with the firstmain gear, but if the said linear speeds vary, the permitted limitedamount of relative rotary movement occurs between the intermediate gearsand the teeth of the friction intermediate gear are caused to projectover the gaps, d

between the teeth of the free'intermediate gear. 7

2. Automatic means for protecting the teeth of two main toothed gearwheels, as

claimed in claim 1, in which-the connection; including a lost motiondevice permitting a limited amount of angular play between theintermediate gears comprises one or more projections carried by one ofthe intermediate gear wheels, which project into one or morecircumferential slots in the other said intermediate gear, the saidslots permitting circumferential movement over the projec tions up tohalf the pitch of the teeth of the intermediate gears.

3. Automatic means for protecting the teeth of two main toothed gearwheels, as claimed in claim 1, in'which spring means are employednormally to keep the teeth of the intermediate gears in line, for thepurposes set forth.

In witness whereof I afiix my signature.

JAMES POTTS.

